* add wrapping key endpoint
* change how wrapping key is stored
* move wrapping key func to backend
* refactor wrapping key generation
* Initial unit tests for Transit wrapping key endpoint
* Wire up wrapping key unit tests to actual implementation.
* Clean up Transit BYOK wrapping key tests and imports.
* Fix Transit wrapping key endpoint formatting.
* Update transit wrapping key to use lock manager for safe concurrent use.
* Rename some Transit wrapping key variables. Ensure the Transit wrapping key is correctly typed and formatted in a unit test.
* Fix spacing issue in Transit wrapping key endpoint help string.
Co-authored-by: rculpepper <rculpepper@hashicorp.com>
